let arr = ['../img/f14.jpg',
    '../img/f16.jpg',
    '../img/f17.jpg',
    '../img/f18.jpg',
    '../img/f19.jpg',
    '../img/f20.jpg',
    '../img/f16.jpg',
]
let img = document.querySelectorAll('img')
let seckillWrap = document.querySelector('.seckill-wrap')
let seckill = document.querySelector('.seckill')
let span = document.querySelector('span')
for (let i = 0; i < img.length; i++) {
    img[i].onclick = function () {
        for (let j = 0; j < img.length; j++) {
            if (i === j) {
                let arrSrc = arr[j]
                seckill.src = arrSrc
                seckillWrap.style.display = 'block'
            }

        }
    }
}
span.onclick = function () {
    seckillWrap.style.display = 'none'
}